Line a 13x9-in. pan with foil; grease foil with 2 teaspoons butter. Cube remaining butter. In a Dutch oven, combine sugar, corn syrup and 1 cup cream. Bring to a boil over medium heat, stirring constantly. Slowly stir in remaining cream. Cook over medium heat until a candy thermometer reads 250° (hard-ball stage), stirring frequently. Remove from the heat; stir in cubed butter and vanilla until well mixed, about 5 minutes. , Pour into prepared pan. Cool. Remove foil from pan; cut candy into 1-in. squares. Wrap individually in waxed paper; twist ends.